SecretAgentMan

Hi!

My 4-pot 305 mm AP's are acting a bit weird after their first real track day.

They're run in properly, and I've always been extra careful with them, letting them cool off while the car is moving after I've had a bit of fun.

It's a "regular" 16" kit with the stock pads and discs.

This trackday was a bit special, long straight, and a tight-ish right hander, going from 120 to 60 in a full on stop.
They did very well for ~6 laps, then they started to judder something terrible.

I let them cool off properly, drove it a little bit, the judder was still there, but not as much, and it seemed to go away more and more when I used them. Almost as if the pads where the cause for this.

Problem solved I thought....

Now they start to judder a little bit when they are worked, which makes me think it's a problem with the discs.

*hmmm*

Any ideas?

Surely they shouldn't have a problem with this? I'm thinking warrenty claim.

/J

AndyMc

Hi J

Are you sure its not your rear brakes that are at fault?.
I also started to get a judder after fitting the same AP kit on my MY98 and thought it was the front brakes but it turned out to be my non-vented rears,they do run a lot hotter if you have uprated fronts.

People on here seem to think that the rears do very little work but this doesn't seem to be the case on my car.If I go for a drive then stop the rear calipers are always much hotter than the fronts.You could try this on your car!.

Heres a story for you, when I first got the AP kit I tried a load of stops from naughty speeds one after the other to see what happened.After about 10 stops the pedal started to get spongy which I was not expecting (I thought the brakes would be unfadeable ) so I pulled over to see how hot the calipers were.When I looked at the rear brakes I could't believe my eyes, the discs were actually glowing and the pads were smoking slightly.The calipers were far to hot to touch as was the centre of the wheel.By comparision the front calipers were much cooler and the wheel was only warm.

Does your car have vented rears?
How many miles have they done?

Andy

SecretAgentMan

The rears are vented, they've done a few miles, but I don't think they're the problem.

The judder is felt through the steering wheel, which indicates problems at the front.

The strange bit is that it comes back when they've gotten a bit of (ab)use.

Otherwise they're perfect.

/J

SecretAgentMan

Problem solved!

It seems as if the stock AP "japan" pads caused the judder, a new set of Pagid Blues has sorted it.

Only problem was that the 305mm kit and the pagid pads didn't exactly suit eachother, the pads has to be machined a little to get clearance from the bells.

*doh*

Anyway, quickly sorted with the trusty old Dremel.

The big issue is the backing plate, I'll have to machine that one as well, since it'll make contact with the bell when the pads get worn enough.

The pads are great, but this sucked a tad.

/J

Davvers

Pagid will do the correct size for the 305mm kit, their code number is U2126 and its a 42mm wide pad not the 46mm you need (it sounds as though you have the 50mms at the moment)